I built this list mostly for casual games as a fun concept, however I'm looking to potentially take it to a local tournament in a few months. I'm not well experienced with 8th, and would appreciate some thoughts on its viability in competitive play.

General plan is all the infantry except the small PF unit sit inside the walls (fireblade outside to buff), with HHs nearby and piranhas to screen transports/hunt tanks. The walls also reduce the number of units to deploy significantly. Darkstrider and breachers can capture objectives or apply pressure down field as needed later in the game, with any piranhas that (likely won't) survive. The idea is to take out enemy anti-tank quickly, and deprive most weapons of good targets with no infantry exposed; ideally the enemy targets my HHs first and leaves the troops to make it to late game unscathed.

I'm not totally convinced on the Piranhas, but I needed some anti-tank outside the HH blob, and I have the models.